Dignum - Nolan, Mullingar to Albany, NY

I am looking for information on the families of Jane Nolan (1801) daughter of John Nolan and Mary Daly and John Dignum (1800) son of James Dignum and Ellen Kilroy of Mullingar, Co. Westmeath. Jane married John Dignum prior to 1828 and had the following children while living in or near Mullingar.

Michael 1828
James 1830
Ann 1834
John - 1835
Thomas 1838
Patrick - 1840.

I have not been able to locate the ship manifest for this family, so they may have traveled through Canada. By 1850, the family lived in Albany, NY and Jane was deceased. John Dignum's brother James and his wife Ann (Fox) were also in Albany. They emigrated in 1834 and their five daughters were born in the city. I have not found any connection with Albany Nolan's and this family, but there could be some. I would welcome any information on the Dignum Nolan families in Westmeath or the US.